<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<p onclick="mes(this)">1223</p>
<script>
function mes(obj){
    var strDate = 123123123;
    obj.innerHTML=strDate;
    }
</script>
</body>
</html>